NAME
    POE::Component::Resolver - A non-blocking getaddrinfo() resolver

VERSION
    version 0.900

SYNOPSIS
            #!/usr/bin/perl

            use warnings;
            use strict;

            use POE;
            use POE::Component::Resolver qw(AF_INET AF_INET6);

            my $r = POE::Component::Resolver->new(
                    max_resolvers => 8,
                    af_order => [ AF_INET6, AF_INET ],
            );

            my @hosts = qw( ipv6-test.com );
            my $tcp   = getprotobyname("tcp");

            POE::Session->create(
                    inline_states => {
                            _start => sub {
                                    foreach my $host (@hosts) {
                                            $r->resolve(
                                                    host    => $host,
                                                    service => "http",
                                                    event   => "got_response",
                                                    hints   => { protocol => $tcp },
                                            ) or die $!;
                                    }
                            },

                            _stop => sub { print "client session stopped\n" },

                            got_response => sub {
                                    my ($error, $addresses, $request) = @_[ARG0..ARG2];
                                    use YAML; print YAML::Dump(
                                            {
                                                    error => $error,
                                                    addr => $addresses,
                                                    req => $request,
                                            }
                                    );
                            },
                    }
            );

            POE::Kernel->run();

DESCRIPTION
    POE::Component::Resolver performs Socket::GetAddrInfo::getaddrinfo()
    calls in subprocesses where they're permitted to block as long as
    necessary.

    By default it will run eight subprocesses and prefer address families in
    whatever order Socket::GetAddrInfo returns them. These defaults can be
    overridden with constructor parameters.

  PUBLIC METHODS
   new
    Create a new resolver. Returns an object that must be held and used to
    make requests. See the synopsis.

    Accepts up to two optional named parameters.

    "af_order" may contain an arrayref with the address families to permit,
    in the order in which they're preferred. Without "af_order", the
    component will return addresses in the order in which
    Socket::GetAddrInfo provides them.

            # Prefer IPv6 addresses, but also return IPv4 ones.
            my $r1 = POE::Component::Resolver->new(
                    af_order => [ AF_INET6, AF_INET ]
            );

            # Only return AF_INET6 addresses.
            my $r2 = POE::Component::Resolver->new(
                    af_order => [ AF_INET6 ]
            );

    "max_resolvers" controls the component's parallelism by defining the
    maximum number of sidecar processes to manage. It defaults to 8, but
    fewer or more processes can be configured depending on usage
    requirements.

            # One at a time, but without the pesky blocking.
            my $r3 = POE::Component::Resolver->new( max_resolvers => 1 );

   resolve
    resolve() begins a new request to resolve a domain. The request will be
    enqueued in the component until a sidecar process can service it.
    Resolve requires two parameters and accepts some additional optional
    ones.

    "host" and "service" are required and contain the host (name or Internet
    address) and service (name or numeric port) that will be passed verbatim
    to getaddrinfo(). See Socket::GetAddrInfo for details.

    "event" is optional; it contains the name of the event that will contain
    the resolver response. If omitted, it will default to
    "resolver_response"; you may want to specify a shorter event name.

    "hints" is optional. If specified, it must contain a hashref of hints
    exactly as getaddrinfo() expects them. See Socket::GetAddrInfo for
    details.

    "misc" is optional continuation data that will be passed back in the
    response. It may contain any type of data the application requires.

   DESTROY
    This component is shut down when it's destroyed, following Perl's rules
    for object destruction. Any pending requests are canceled, and their
    responses will be errors.

  PUBLIC EVENTS
   resolver_response
    The resolver response event includes three parameters.

    $_[ARG0] and $_[ARG1] contain the retrn values from
    Socket::GetAddrInfo's getaddrinfo() call. These are an error message (if
    the call failed), and an arrayref of address structures if the call
    succeeded.

    The component provides its own error message, 'component shut down'.
    This response is given for every pending request at the time the user
    shuts down the component.

    $_[ARG2] contains a hashref of information provided to the resolve()
    method. Specifically, the values of resolve()'s "host", "service" and
    "misc" parameters.

BUGS
    There is no timeout on requests.

    There is no way to cancel a pending request.

LICENSE
    Except where otherwise noted, this distribution is Copyright 2011 by
    Rocco Caputo. All rights reserved. This distribution is free software;
    you may redistribute it and/or modify it under the same terms as Perl
    itself.

